Communicating high data rates in limited bandwidth requires more complicated modulation schemes (e.g., OFDM, 64QAM, etc.) that depend on high linearity circuits. Furthermore, users must stay within their allocated channel and not encroach on adjacent channels—this also requires high linearity operation. It is also desirable to perform these operations with limited power consumption and/or dissipation (e.g., for airborne applications, Unmanned Aerial Vehicles (UAVs), batter power applications, etc.). However, traditional analog and RF circuit design techniques for high linearity applications require high power consumption and dissipation.
Techniques have been developed to run radio frequency (RF) and analog circuits at lower power and correct for nonlinearities and improve linearity with digital signal processing (e.g., Nonlinear Equalization (NLEQ) for receivers and Digital Predistortion (DPD) for transmitters). For robust operation over temperature, changing antenna impedance and aging of circuits, a monitor receiver is typically added to the system to monitor these effects and adapt the linearization processing parameters. In a system with multiple receive and transmit channels, implementing a monitor receiver for each channel adds substantial additional circuitry and complexity, resulting in increased cost, weight, power, and volume.